Signaling system for railroads



Nov. 23, 1937. s. N. WIGHT SIGNALING SYSTEM FOR RAILROADS Filed July 14,1954 INVENTOR Patented Nov. 23, 193 7 OFFICE SIGNALING SYSTEM FORRAILROADS Application July 14, 1934, Serial No. 735,267

8 Claims.

This invention relates to signaling systems for railroads, and moreparticularly to the control of signals associated with track switchesarranged to be operated either by power or by hand.

In certain applications of power-operated track switches, it isdesirable to provide means by which the switch can be readilydisconnected from the power operating means and moved and 10 locked by amanipulation of a hand-throw device; and switch machines are sometimesequipped with a means, commonly known as a dual control selector, whichpermits the operating gearing of the switch machine to be disconl5ne'cted from the operating motor and coupled to a hand-throw lever, sothat for switching moves, or in the event of failure of the power means,the switch can be operated and locked by hand.

When such a dual control selector is employed '0 with a power-operatedswitch, it is desirable to break the circuits for clearing the signalsgoverning traflic over the switch when the selector lever is in thehandthrow position, so that as long as the switch is being operated byhand for switching movement, the signals cannot clear.

Among other things, this affords signal protection for the train doingthe switching; and even if the signals are manually controlled by anoperator at a central control point, and would not ordinarily clear whenthe switch has been thrown and locked, the same control of the signalsis desirable in order that there may be no divided responsibilitybetween the operator and the trainman operating the switch by hand.

Under some conditions, however, it is also desirable that the signals beallowed to clear when safe to do so, even though the switch is inconditionto be operated by hand. For example, there may be some failureor other condition which 40 prevents operation of the switch by power;and to avoid train delays, it is expedient to permit the switch to bemoved and locked in the desired position by hand, and allow trains topass over the switch under the protection of the signals.

5 With these considerations in mind, in accordance with this invention,it is proposed to provide in connection with a switch machine equippedwith a dual control selector device so .that the switch points may beoperated and 50; locked by hand, another manually operable device, whichwould be manipulated as occasion may require, and preferably only underthe instructions of the operator, to permit the signals to clear whilethe switch is in condition to be operated by hand.

The accompanying drawing illustrates in a simplified and diagrammaticmanner the principles and functions of the invention, the parts andcircuits being shown more with a view of facilitating an understandingof the invention, rather 5 than with the idea of showing the structuralorganization of the switch machine, signals, and associated parts, whichare well-known in the art, and may take Various forms.

Referring to the drawing, a track switch SW, 10'

with associated signals l, IA, 2, and 2A for governing traffic over theswitch, is illustrated conventionally. The track switch SW is assumed tobe connected to a power-operated switch machine, diagrammatically shownas SM, equipped 15' with the usual point detector contacts, and a dualcontrol device. A switch machine of the type contemplated is disclosed,for example, in the patent to W. K. Howe, No. 1,466,903, September 4,1923.

The power operation of this switch machine SM is assumed to becontrolled in some suitable manner (not shown) by an operator at adistant point, either by direct line wire control, or through the agencyof a code type communica- 25 tion system, in accordance with theprinciples and practices in interlocking and centralized traffic controlsystems.

This switch machine SM is provided with suitable point detectorcontacts, such as disclosed, 30 for example, in the patent to R. C.Leake, No. 1,442,685, January 16, 1923, which are closed in accordancewith the position and locked condition of the switch points. Suchcontacts are illustrated conventionally as comprising two movablesignals governing trafiic over the switch in accordance with the commonpractice, as indicated conventionally by dotted lines. It is assumedthat the clearing of the signals, subject to con trol by track circuitsand the energized condition of the relay WP, is under the control of thedistant operator in a suitable manner not shown.

The switch machine SM is also provided with a suitable dual controldevice, including a selector lever, illustrated diagrammatically as SL,

which may be operated to connect the point 5 throwing and lockingmechanism of the switch machine either to the motor, or to a hand-throwlever, so that the switch points may be moved and locked either by poweror by hand operation. A dual control device of this type is disclosed,for example, in the patent to W. C. McWhirter, No. 1,716,787, June 11,1929. The selector lever SL actuates contacts shown diagrammaticallywhen in the positions for power and hand operation.

As diagrammatically shown, a switch throw rod actuating shaft M, carriesa coupling member I 5 splined thereto, as at I5 the coupling member l5being slidable by lever SL connected to, and movable with, selectorlever SL, to operatively connect it either to the member I 6 poweroperated by the switch machine SM, or to the hand operated member l1,operated by ahand throw device lB.

In accordance with this invention, an additional manual control deviceis provided. As illustrated, this device is in the form of a push-buttonor suitable hand switch PB and a stick relay S. The push button PB islocated near the switch at a point conveniently accessible to atrainman, and is preferably enclosed in a locked or sealed box.

Under ordinary conditions, with the selector lever in the power positionshown, the switch machine is in condition to be operated by power andthe relay WP is controlled by the point detector contacts 56, the supplyof current to these contacts from one terminal of the battery or othersource, indicated by being through contacts I and 8 closed with theselector lever SL in the power position. The switch machine may becontrolled by the operator, and the signals may clear dependent upon theposition and locked condition of the switch as manifested by theenergization of the relay WP.

Assuming now that a train desires to do switching over the switch inquestion. The trainman, acting under instructions from the operator,moves the selector lever SL from the power position shown to the otherdotted line position, opening contacts 'l8 in so doing. This brakes thesupply of energizing current for the relay WP, and the circuits forclearing the signals are broken at the same time the switch machine isput in condition for hand-throw operation. The trainman may throw andlock the switch points as required, and direct the switching operationsby hand signals.

During such switching operations, all of the signals I, IA, 2 and 2Agoverning traific over the switch are held at stop, and consequently,all the signals, such as the signal 3, governing traific toward theswitch, indicate caution and warn any approaching train to slow down andstop, even though the track circuits controlling the stop indicationsfor such approach signals do not happen to be occupied at the particulartime. In this Way, adequate signal protection is provided for the trainmaking the switching moves, even though the operator shouldthoughtlessly or accidentally attempt to clear any of these signals.

Assume now that for some reason, due to failure of power, breakage ofparts, or the like, the switch machine cannot be operated by power.Under such circumstances, the switch must be thrown by hand. To do this,the trainman moves the selector'SL to the hand-throw position the sameas when making a switching move; and when this is done, contacts 'l--Bare open so that the signals governing trafiic over the switch cannotclear.

Such failure of power operation of the switch machine, however, may besuch that the switch points can be moved by hand and properly locked;and to avoid unnecessary stopping of trains making movements over theswitch in its existing position, it is desirable that the signals bepermitted to clear. In such a case, the trainman, acting under theinstructions of the operator, pushes the push-button PB to pick up thestick relay S through a pick-up circuit readily traced on the drawing,and then releases the button. With the selector lever in the hand-throwposition, the stick relay S is stuck up by a stick circuit through thecontacts 9 and iii and its own front contact H and when the push-buttonPB is released and returns to its normal position, current is suppliedto the point detector contacts 5 and 6 to energize the relay WP throughthe push-button PB and front contact l2 of the stick relay S. If theswitch points are over and locked, the relay WP is energized, and this.permits clearing of the signals.

The switch may be left in this condition so long as the failure of poweroperation exists; and trains making movements over the switch in itsexisting position may do so without stopping, while other trains maystop and operate the switch by hand as required. In this way, themovement of trailic is materially facilitated in the event of powerfailure or the like.

When the power has been restored, or repairs made, so that the switchmachine can be operated by power, selector lever SL is placed in thepower position. This opens the contacts 9 and ID, and breaks the stickcircuit for the relay S, restoring the parts to the normal condition.

This invention provides for controlling the signals governing trafiicover a switch in a way which takes care of train movements under normaloperation of the switch by power, switching moves under hand-throwoperation of the switch, and also train movements under special oremergency conditions of failure of power operation. One characteristicfeature of the invention is the use of two separate manually operabledevices, one

the usual selector lever by which the switch ma-' chine is placed incondition for power operation or hand-operation, and the other the pushbutton PB and stick relay S, or equivalent means, which may be alsooperated when occasion requires, to permit clearing of the signals withthe switch machine on hand-throw.

The specific embodiment of the invention shown and described is merelyillustrative; and various adaptations and modifications may be madewithout departing from the invention.

What I claim is:-

1. In a signaling system for railroads, a track switch, a switchmachine, dual control means conditioning the switch to be moved andlocked by power or by hand, signals governing traffic over the switch,and manually operable means at the switch operable for clearing of thesignals while said switch machine is in condition for hand operation dueto the position of the dual control means.

2. In a system of signaling for governing train movements over trackswitches, the combination with power means for operating the switch, a

hand-throw device for moving and locking the switch, a selector leverfor rendering either the power means or the hand-throw device effective,and signals governing trafiic over the switch; of manually operablemeans separate from the said selector lever for clearing the signalswhen said selector lever is in the hand-throw position.

3. In a system of the character described, the combination with a trackswitch, power means for operating the switch, a hand-throw device formoving and locking the switch, signals governing tratfic over theswitch, circuits for controlling said signals governed in accordancewith the position and locked condition of the switch, a selector leverfor optionally connecting the switch to said power means or saidhand-throw device, said lever when in the hand-throw position breakingsaid signal control circuits, of other manual means for controlling ofsaid signal control circuits while said selector lever is in thehandthrow position.

4. In a system of signaling of the character described, a track switch,contacts operated in accordance with the position and locked conditionof the switch, a switch machine including power means and a hand-throwdevice for moving and locking the switch, a selector lever for renderingeither the power means or the hand-throw device eifective, signalsgoverning traffic over the switch and having circuits controlled by saidcontacts, means operated by the movement of the selector lever to thehand-throw position for breaking said signal circuits, a stick relayacting when energized to supply current to said signal circuitsindependently of the position of the selector lever, a manually operablecircuit controller for energizing said stick relay, and a stick circuitfor said stick relay closed only while the selector lever is in thehand-throw position.

5. In a signaling system for railroads, a track switch, a switchmachine, dual control means for conditioning the switch to be moved andlocked by power or by hand, signals governing traffic over the switch,said control means, when in hand position, putting the signals to stop,and manually operable means at the switch operable to allow clearing ofthe signals at the option of the trainman while said switch machine isin condition for hand operation due to the position of the dual controlmeans, provided the switch is in locked condition. 1

6. In a system of signaling of the character described, a track switch,contacts operated in accordance with the position and locked conditionof the switch, a switch machine including power means and a hand-throwdevice for moving and locking the switch, a selector lever for renderingeither the power means or the hand-throw device effective, signalsgoverning traffic over the switch and having circuits controlled by saidcontacts, means operated by the movement of the selector lever to thehand-throw position for breaking said signal circuits, a stick relay, amanually operable controller movable from normal to operated position toenergize the stick relay, a stick circuit for the stick relay closedonly while the selector lever is in the hand-throw position, and acircuit for supplying energy to said signal circuits requiring the stickrelay to be energized and the controller in its normal position.

7. In a system of signaling of the character described, a track switch,contacts operated in accordance with the position and locked conditionof the switch, a switch machine including power means and a hand-throwdevice for moving and locking the switch, a selector lever for renderingeither the power means or the hand-throw device effective, signalsgoverning trafiic over the switch and having circuits controlled by saidcontacts, means operated by the movement of the selector lever to thehand-throw position for breaking said signal circuits, means, includinga manually operable controller movable from a normal to an operatedposition, requiring movement of the controller to its operated positionand then back to its normal position, for clearing the signals when theselector lever is in the hand-throw position.

8. In a system of signaling for governing train movements over trackswitches, the combination with power means for operating the switch, ahand-throw device for moving and locking the switch, a selector leverfor rendering either the power means or the hand-throw device'effective,and signals governing traffic over the switch; of means, including amanually operable controller movable from a normal to an operatedposition, requiring movement of the controller to its operated positionand then back to its normal position, for clearing the signals when theselector lever is in the hand-throw position.

SEDGWICK N. WIGHT.

